It was widely felt in both the South and North Islands, as far north as Auckland, causing damage and knocking out power."

I felt it all the way in Wellington. The house shook so much I thought the earthquake was based in Wellington. A few things fell down. Also, lots of aftershocks, some rather big, some small but still noticeable.

Then the tsunami sirens went off so I had to get out of bed and gather a few items. Currently we are all further inland. I believe the sirens have now stopped, but we'll wait a bit more.

Staff: Mentor

As to why there are varying figures on the scale (USGS changed from 7.4 to now 7.9, Potsdam had 7. 8 and I've heard 6.6 by local reports):
A geology professor on a news channel here said: "It's difficult to determine the exact magnitude because it lasted so long, more than 2 minutes." Aftershocks are still occurring, but the danger of a major tsunami is likely banned.

It was so scary, I was nearly in tears while we drove inland thinking our home could be gone. You hear about this happening overseas, but you really know what it feels like when you're faced with that situation.

A lot of schools and business' will be closed in Wellington and Christchurch. The trouble is NCEA end of year exams are happening.
"NZQA are yet to issue a statement on exams but they have talked to RNZ. A spokeswoman said most schools around the country should be open for business, but others in the quake and tsunami zones may not be. It may be the case at some schools that their practice exam results are used in place of exams, using the standard "derived grades" process."

As to why there are varying figures on the scale (USGS changed from 7.4 to now 7.9, Potsdam had 7. 8 and I've heard 6.6 by local reports):
A geology professor on a news channel here said: "It's difficult to determine the exact magnitude because it lasted so long, more than 2 minutes." Aftershocks are still occurring, but the danger of a major tsunami is likely banned.

Yes, the initial report from GNS ( in NZ) was 6.6, it was horribly under estimated ... my system was in overload for some 40 minutes and when the USGS report of 7.5 came out I knew that would be much closer to reality.
The really interesting thing about this event and the subsequent ones is that they are very widespread but in a line from the original M7+ and trending NE'wards
The whole area fired up. I have seen this several times over the years around the world but not like this in New Zealand.
And interestingly, almost all of the larger following events were not even in the area of the main shock.

So far 2 people have been reported killed, one when their house collapsed on them

I've been watching davenn's observation of the NE trend to the "aftershocks" and they are, indeed, unusual. Until the latest one, a 6.8 near the first quake, they (the later quakes) are moving closer to Wellington. It looks like they are along the offshore projections of the Wellington and Wairarapa faults on the other island. Very interesting and unnerving if I lived in Wellington.

Staff: Mentor

I took a screen shot of the USGS page of recent earthquakes.

The Mag 7.8 is the blue dot, and the second Mag 6.5 is the red dot. North of Kaikoura, straddling the fault are a Mag 6.5, 6.2 and 6.1 earthquakes. To the northeast is a cluster of Mag 5s near Ward, NZ, Lake Grassmere and Cape Campbell.

But the comment from GNS about it being a double event, is a possibility, it does happen periodically
I'm going to be really interested to see if any visual ground surveys of the region of the main event shows any surface faulting
It may not happen because of the depth.

Nelson to Kaikoura is about 130 km (80.7 miles). Is it possible Nelson received some P-waves? Possibly from the Mag 6+ group that were 12 to 23 km N to NNW from Kaikoura toward Blenheim?

A number of years ago, I was about 60 miles from a Mag 6.5, and I felt the P-wave then S-wave. I was sitting on a large couch, and all of a sudden, it started shaking like an imbalanced washing machine. Moments latter, it started bouncing.